Recently, in order to reduce air pollution caused by an exhaust gas of a vehicle, the vehicle is manufactured based on studies of obtaining driving power by using an internal combustion engine and/or an electric motor. In this regard, the vehicle has evolved in an order of a hybrid car, a plug-in hybrid car, and an electric car.
As well known, the hybrid car and the plug-in hybrid car include an internal combustion engine, an electric motor, and a battery pack, and the electric car includes an electric motor and a battery pack without an internal combustion engine.
The battery pack is configured to be chargeable inside and/or outside of the electric car. The battery pack includes a battery module including a battery stack and a plurality of ducts. The battery stack includes a plurality of cartridges that are sequentially stacked on each other, and at least one battery cell provided between the plurality of cartridges. The cartridge includes an air flow path penetrating one side surface to the other side surface of the cartridge, which face each other. The plurality of ducts surround, in a sandwich structure, two side surfaces of the battery stack where the air flow path is exposed, and guide a flow of air flowing into the plurality of cartridges and flowing out from the plurality of cartridges.
In this case, at least one of the plurality of ducts includes therein a blast fan, a driving motor, and a harness to compel inflow and outflow of air around the battery stack. The blast fan is connected to the driving motor and rotates, thereby forcing air to flow. The driving motor transmits driving power to the blast fan to adjust the number of rotations of the blast fan. The harness is connected to the driving motor to apply power to the driving motor or transmit an external electric signal for controlling a rotation speed of the blast fan to the driving motor while the blast fan rotates.
The harness is electrically connected to a battery management system (BMS) outside of the duct by penetrating the duct from inside to outside of the duct. Here, the BMS is a computing device controlling overall operations of the battery pack, including charging and discharging of the battery pack.
The harness includes wires bound in one unit and a coating of a resin material surrounding the wires. A cross-section of the harness is not uniform along a length direction of the harness because sectional shapes of the wires differ according to locations due to kinks and/or leaning of the wires in the harness.
Accordingly, the duct has a gap between an inner surface of a through hole and an outer surface of the harness, at a region where the harness penetrates the duct. The gap between the duct and the harness hinders the duct from being completely sealed. When the duct is not completely sealed, blasting pressure of air is decreased. As a result, an air flow generated inside the duct by the blast fan becomes irregular, and thus cooling efficiency of the battery stack deteriorates.